SALT LAKE CITY — Rep. Jason Chaffetz accused the White House and the State Department on Monday of hiding documents to hinder a congressional investigation into an attack that killed four Americans in Libya nearly two years ago.

"It's a very concerted effort. I don't think there's a case to be made other than obstruction of Congress at this point," the Utah Republican said.

His claim comes as House Speaker John Boehner, R-Ohio, organizes a select committee to look into the Sept. 11, 2012, assault on the U.S. consulate in Benghazi that left Ambassador Christopher Stevens and three others dead.

House Democrats call the effort a waste of time and money that the GOP is using to play politics.

He points to emails involving then-U.N. Ambassador Susan Rice that the State Department changed from unclassified to classified shortly before releasing them to the House Oversight and Government Reform Committee. Chaffetz serves on the committee.

Furthermore, he said, the same emails that the conservative watchdog group Judicial Watch obtained under the Freedom of Information Act have more information — speficially the names of senders and recipients — than what Congress received.

In each case, the body of the emails was redacted. They now aren't slated to be declassified until 2037.

"These documents that we're trying to look at that the White House is playing games with provide another clue," Chaffetz said. "I don’t know what’s underneath them, but we ought to be able to look at them."

The White House initially described the attack as a response to an anti-Islamic video that had sparked protests at the embassy in Cairo and elsewhere, which Rice described on several television talks shows.

"I find that answer to be false," Chaffetz said.

One of the most vocal critics of the Obama administration on Benghazi, Chaffetz said he doesn't know if he will be named to the select committee to be headed by Rep. Trey Gowdy, R-S.C.

Gowdy is a former federal prosecutor and a member of the House Oversight and Government Reform Committee, which has focused intensely on the Benghazi attack.

The House could vote early as this week on a resolution outlining the size, scope and budget of the special panel. House Democrats oppose forming the committee and see nothing but politics behind Republicans' continued investigations.